Flow Patterns around the Flat Plates in a Turbulence Promoter : 1st Report, Effect of Duct Wall of Flow Passage

Abstract

To separate substances from solutions, membranes have been used. However in these cases, the phenomena of concentration polarization on the surface of the membrane and the growing of gel layers can not be avoided. These phenomena slow down the filtration. Creating a turbulence on the surface of the filter is one of the effective ways so prevent these phenomena on the filter surface. However, there are few reports which provide details about them. This report is a theoretical and experimental analysis of a flow patterns occuring around a single flat plate, the simplest type of turbulence promoter. The relationships between the Reynolds Number Re and the coefficient of loss, the coefficient of pressure, and the coefficient of pressure fluctuation were examined. The new non-dimensional number M which indicates the effect of the duct wall is proposed and the coefficient of loss ξ can be expressed as a function of the number M. And the relationships between the coefficient of loss in experiments and the number M are coincident with the theoretical values.